1. Field of the Invention
This invention relates to the design and operation of electronic equipment, including computer systems, and, more particularly, to a mechanism for selectively determining a mode of operation of such equipment, wherein the mechanism may be rendered substantially inaccessible to unauthorized intrusion.
2. Description of the Related Art
It is frequently desirable in the design and operation of electronic equipment, including, for example, computer systems, that various functions of the equipment be rendered individually enabled or configurable by the user. With specific reference to computer systems, configuration information had been formerly provided to the system processor by the computer user's selection of the state of a bank of DIP mechanical switches that were physically installed on the computer motherboard. More recently, configuration information is stored in a CMOS RAM, and the processor reads the configuration data during the initialization process. In addition to configuration data, it is often desirable that certain other aspects or features of the computer system operation be selectable by the user. Often the user is simply presented with an option either to enable or disable a function, or to select between two or more available modes of operation.
An example of computer functionality that might require or accept user's assertion to enable or disable the function is the publication of the computer system serial number. This represents a relatively new feature in personal computer systems, and concern has been expressed with respect to the privacy implications attendant publication of system serial numbers. In order to mitigate this concern, it has been proposed that the function be selectively disabled, under user control, through the operation of installed software. However, in response to anticipated suspicions that the software may not uniformly operate as endorsed, a more tangible mode, such as a jumper wire on the motherboard, has been considered as an alternative means for selectively enabling or disabling the function. Of course, connection of the jumper wire requires opening the computer cabinet, setting the jumper, and then closing the cabinet. Because there may be some circumstances where the serial number must be conveyed, for example, in order to gain access to certain protected resources, such as some sites on the worldwide web, jumper wire connection and disconnection promises to become a recurrent process, and a recurrent nuisance. An externally accessible switch would seem to be preferable, to the extent that the inconvenience of opening and closing the computer cabinet may be circumvented.
As another example, the advent of e-commerce transactions has given rise to the requirement that PCs have the capability to store and deliver digital certificates, security tokens, and other similar information. Because of the threat that such information may be hacked into and the user's security compromised, it appears judicious to have this functionality normally disabled, but conveniently enabled when the computer user desires to engage in e-commerce or other secured or verified transactions. Conversely, in the business environment, an IT administrator might desire to have the function "almost always ON" in an employee's computer. In this situation, the end-user employee would be denied the capability of countervailing the setting established by the IT administrator.
Accordingly, what is desired is a technique for selectively enabling or disabling a function to electronic equipment, such as computer systems. The technique should be convenient to use, yet provide security from unauthorized, or otherwise unwarranted, intrusion.